Apparatus for preparing explosives



. Dec. 25, 1951 F. A. F. CRAWFORD APPARATUS FOR PREPARING EXPLOSIVES 2SHEETS-SHEET 1 Filed Dec. 6, 1946 3 wvmvkw, FREDERICK flLEXflN ERFERRIER cmwronb 1951 v F. A. F. CRAWFORD 2,579,474

APPARATUS FOR PREPARING EXPLOSIVES I Filec l De0..6, 1946 2SHEETS-l-IEET 2 FICiTZ FRDERI6K mum DER FfinRmR RAWFOR vture ofnitroglycerine and the like.

Patented Dec. 25 1951 APPARATUS FOR PREPARING EXPLOSIV ES Frederick A.F. CrawfonLWest Kilbride, Scotland, assignor to Imperial ChemicalIndustries Limited, a corporation of Great Britain Application December6, 1946, Serial No. 714,626 In Great-Britain December 7, 1945 4 Claims.1

The present invention relates to an improved process and apparatus forthe continuous manufacture of explosive liquid nitric esters fromrapidly esterifiable liquid polyhydric alcohols and more especially tothe continuous manufac- More particularly the invention relates to a newand improved circulatory process for the manufacture of the aforesaidexplosive liquid nitric esters, wherein the esterifiable organic liquidcompound is continuously nitrated with a nitrating acid medium and theresulting liquid nitric ester is separated from the refuse nitratedacid.

The object of the present invention is to provide a process which can beused with relative safety for the continuous production of liquidexplosive nitric esters'which includes the step of quickly andcontinuously removing by centrifugal separation the liquid. explosivenitric ester from a continuous succession of relatively small quantitiesof a mixture of said liquid explosive nitric ester and refuse nitratingacid resulting from the interaction of aliquid polyhydric alcohol andnitrating acid.

According to the present invention the process for the continuousmanufacture of explosive liquid nitric esters from rapidly esterifiableliquid polyhydric alcohols comprises continuously introducing thealcohol and nitrating acid into a mixing space, subjecting theincipiently reacted mixture to continuous circulation by impelling it ata rate sumcient to maintain turbulence throughout the circulation out ofthe lower part of said space through a narrow externally cooled tubularconduit external to said space to a horizontally remote locus at whichthe reaction is complete and back'into the upper part of said space,bleeding oil a portion of the substantially completely reacted mixtureat said remote locus, and separating by continuous centrifugal actionthe liquid explosive nitric ester from the bled ofi portion while thelatter is still in emulsion form.

Preferably the resulting continuously separated liquid explosive nitricester is immediately emulsified with an .aqueous Washing medium.

So long as the liquid explosive nitric ester remains emulsified in therefuse nitrating acid in its passage between the nitrating vessel andthe centrifugal separator there is no danger of any detonation arisingin the centrifugal separator being carried back through the column ofliquid to the nitrator. The proviso according to the present inventionthat the incipiently reacted mixture is to be impelled at a ratesufficient to maintain turbulence throughout the circulation 1 of thereaction mixture past a horizontally re- ..mote locus makes it possiblefor the nitrating vessel and the centrifuge to be sufficiently distancedthat no explosion debris from either is likely to reach theother.

Apparatus suitable for the process according to the invention, comprisesa mixing vessel having a lower portion of larger diameter accommodatinga rotary impeller and an upper neck portion. of smaller diameter open atthe top accommodating the shaft of the said impeller, inlets for theliquid reagents, an external circulation pipe jacketed oversubstantially its whole length and leading from the vessel at the levelof said impeller to a horizontally remote locus and returning into theneck of said vessel, if desired the impeller shaft may have stirrerblades, a continuous centrifugal separator in the vicinity of said locusat a lower hydrostatic level than said vessel and a branch communicationfrom a portion of said external circulation pipe at said locus enteringsaid centrifugal separator;

said separator having an outlet for the refuse acid and anoutlet for theseparated liquid explosive nitric ester leading to re-emulsifyingapparatus in which said ester is emulsified in an aqueous washing liquidin close proximity to said separator. The centrifugal separator and thereemulsifying apparatus are preferably shielded by a surrounding bafliestructure, and a bafile structure through which the external circulatingpipe passes is preferably interposed between the mixing vessel and theremote part of the circulating pipe.

The invention has the advantage that no matter how far distant is thelocus from which the stream is bled off to the separator, the wholestream circulating from the mixing vessel to said locus and back againis maintained in emulsion by its turbulent flow. As the distance theemulsion has to travel from said locus to the separator, over which itis not maintained in turbulent flow by the impelling means, may be madevery short, it follows that the horizontal distance between theseparator and the mixing vessel may be made very considerable withoutany separation of the emulsion travelling between the two vessels takingplace, and hence without the possibility of a detonation in one of thevessels being communicated through the liquid 7 1 is a bleed-off pipeand 6 is a centrifugal separa-.

tor, I is a pipe in which the separated liquid 6X.-

plosive nitric ester delivered through an outflow pipe I5 in water bymeans of a water jet IS, the pipe I leading to a washing tank not shownin the drawing. 8 is a refuse acid outflow pipe, 9 is an emergencyrunaway cock, I0 is a concrete lined trench, l I is a concrete explosionbafiie run ning transversely across the trench. I8 is an overflow gutterand I2 is a concrete shielding structure for the centrifugal separator6.

As best seen inFigs. 2, 3a and 4a are the outer walls of the jackets ofthe pipes 3 and 4, and I3 and I4 are the inlet pipes respectively forthe liquid polyhydric alcohol and for the nitrating acid. I! is a bottomclosure for the mixing vessel I which can be destroyed by means'notshown if an emergency should arise for cleaning purposes.

I claim: 1. An apparatus for carrying out the continu- :ous manufactureof explosive liquid nitric esters from rapidly esterifiable liquidpolyhydric alcohols comprising in combination a mixing vessel having thelower portion thereof of larger diameter than the upper portion, 'arotary impeller in said lower portion and substantially occupying theentire space within the same, the shaft of said impeller passing throughthe said upper portion, two inlets for liquid reagents leading into saidupper portion, an external circulation pipe jacketed over substantiallyits entire length leading from the said lower portion at the level ofsaid impeller to a horizontally remote locus and returning horizontallyto the said upper portion for flow of liquid from said larger diameterportion of said mixing vessel to'said smaller diameter portion, and acontinuous centrifugal separator having its inlet connected to saidchculation pipe by a bleed-off pipe connecting at said remote locus.

2. Apparatus for carrying out the continuous manufacture of explosiveliquid nitric esters from rapidly esterifiable liquid polyhydricalcohols comprising in combination a mixing vessel having the lowerportion thereof of larger diameter than the upper portion, a rotaryimpeller in said lower portion and substantially occupying the entirespace within the same, two inlets for liquid reagents leading into saidupper portion, an external circulation pipe jacketed over substantiallyits entire length leading from the said lower portion at the level ofsaid impeller to a horizontally remote locus and returning horizontallyto the said upper portion for flow of liquid from said larger diameterportion of said mixing vessel to said smaller diameter portion and acontinuous centrifugal separator having its inlet connected to saidcirculation pipe by a bleed-off pipe connecting at said remote locus.

3. Apparatus as set forth in claim 2 wherein said separator has anoutlet forrefuse acid and an outlet for the liquid explosive nitricester, said explosive nitric ester outlet leading to apparatusforre-emulsifying in an aqueous washing liquid in close proximity tosaid separator.

4. Apparatus as set forth in claim 2 wherein an explosive bafliestructure is placed between said mixing space and said remote locus.

FREDERICK A; F. CRAWFORD.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,312,119 Hough Aug. 5, 19191,893,447 Schmid Jan. 3, 1933 2,332,527 Pyzel Y Oct. 26, 1943 2,363,834Crater Nov. 28, 1944 2,436,767 Gerlicher Feb. 24, 1948 FOREIGN PATENTSNumber Country Date 38,821 Sweden Apr. 22, 1913

1. AN APPARATUS FOR CARRYING OUT THE CONTINUOUS MANUFACTURE OF EXPLOSIVELIQUID NITIRC ESTERS FROM RAPIDLY ESTERIFABLE LIQUID POLYHYDRIC ALCOHOLSCONPRISING IN COMBINATION OF AMIXING VESSEL HAVING THE LOWER PORTIONTHEREOF OF LARGER DIAMETER THAN THE UPPER PORTION, A ROTARY IMPELLER INSAID LOWER PORTION AND SUBSTANTIALLY OCCUPYING THE ENTIRE SPACE WITHINTHE SAME, THE SHAFT OF SAID IMPELLER PASSING THROUGH THE SAID UPPERPORTION, TWO INTLETS FOR LIQUID REAGENTS LEADING TION SAID UPPERPORTION, AN EXTERNAL CIRCULATION PIPE JACKETED OVER SUBSTANTIALLY ITSENTIRE LENGTH LEADING FROM THE SAID LOWER PORTION AT THE LEVEL OF SAIDIMPELLER TO A HORIZONTALLY TO THE SAID UPPER AND RETURNING HORIZONTALLYTO THE SAID UPPER PORTION FOR FLOW OF LIQUID FROM SAID LARGER DIAMETERPORTION OF SAID MIXING VESSEL TO SAID SMALLER DIAMETER PORTION, AND ACONTINUOUS CENTRIFUGAL SEPARATOR HAVING ITS INLET CONNECTED TO SAIDCIRCULATION PIPE BY A BLEED-OFF PIPE CONNECTING AT SAID REMOTE LOCUS.